Now you can argue (and I will) that the particular gimmick that they chose to explore with the WiiU may be poorly thought out, or that they didn't have a coherent marketing strategy, or any number of other reasons for its current failure. But what I don't get is why anyone would look at the history of their last two consoles and think that at an executive level anyone was going to go "yeah that completely different approach with the Wii was an amazing success, but lets go back to that old strategy, that worked out so well"
Because the Wii's strategy left no room for growth. Even if the Wii U's concept had been successful, the Wii was basically its ceiling because they'd be just recreating the exact same conditions - underpowered hardware missing significant chunks of support by default, which would eventually hurt its early success limiting its potential for growth. I don't see how they look at that, call it a day and attempt to repeat exactly the same strategy.
And if the new gimmick failed to catch on... well, we're seeing the results now. It was a completely unambitious strategy.
Also, the GameCube wasn't just a console on par with the others, it was a console on par with the others released after the clear market leader had more than one year to establish itself. Yeah, that strategy was bad and they shouldn't repeat it, but that doesn't mean that competing was a mistake in the first place. The mistake was attempting to compete like that. Also, look at the numbers now. Compared to the Wii U, the GC was a success.